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Method for nondestructive evaluation of residual stress of aluminum alloy pre-stretched plate by utilizing ultrasonic wave

A pre-stretched plate and residual stress technology, which is applied in the use of sound waves/ultrasonic waves/infrasonic waves to analyze solids, measure forces, instruments, etc., can solve the problem that the detection accuracy is greatly affected by surface roughness, high cost, and consumes a lot of money and time and other problems, to achieve the effect of large thickness application range, improve precision and accuracy, and reduce interference

Active Publication Date: 2015-10-21
广西南南铝加工有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the detection accuracy of this method is greatly affected by surface roughness, and it is only suitable for the detection of residual stress on the surface of thin plates; in addition, the residual stress test block used in this method uses the method of interference fit to introduce residual stress into the residual stress test block, so that Each batch of plates needs to prepare a residual stress test block, this process requires a lot of money and time, and the cost is very high

Method used

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  • Method for nondestructive evaluation of residual stress of aluminum alloy pre-stretched plate by utilizing ultrasonic wave
  • Method for nondestructive evaluation of residual stress of aluminum alloy pre-stretched plate by utilizing ultrasonic wave
  • Method for nondestructive evaluation of residual stress of aluminum alloy pre-stretched plate by utilizing ultrasonic wave

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Experimental program
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Effect test

Embodiment 1

[0055] The tested plate is a 7075 aluminum alloy plate with a thickness of 20mm, a width of 200mm and a length of 300mm. The residual stress test block is cut from the 7075 aluminum alloy pre-stretched plate, and the specifications are 20mm in thickness, 150mm in width and 150mm in length. The XRD ray diffraction method is used to measure the residual stress test block, and the residual stress value of the residual stress test block is measured to be 20 MPa, and is calibrated on the residual stress test block.

[0056] The plate to be inspected introduces residual stress manually, see figure 1 As shown, the 7075 plate 1 was placed in a heating furnace to raise the temperature to 475°C and keep it warm for 4 hours. Then the 7075 plate 1 is quickly transferred to the suspended support 2. A water pipe 4 with a nozzle is fixed at the center of the support 2. The cold water 3 is sprayed to the surface of the 7075 plate 1 through the water pipe 4, so that the 7075 plate 1 is rapi...

Embodiment 2

[0072] The tested plate is a 7050-T7451 aluminum alloy plate, and the tested 7050-T7451 aluminum alloy plate adopts a tensile stress reduction process with a stretch rate of 2.5%. The specifications are 76mm in thickness, 260mm in width, and 260mm in length. The residual stress test block is cut from the 7050-T7451 aluminum alloy plate, and the specifications are 76mm in thickness, 200mm in width and 200mm in length. The residual stress value of the residual stress test block was measured by XRD ray diffraction method to be 18MPa, and was calibrated on the residual stress test block. To measure the residual stress of the tested plate, the steps are as follows:

[0073] (1) The frequency is 15MHz, and the water immersion type ultrasonic flat probe with a diameter of 12.7mm is installed on the ultrasonic equipment, and the frequency spectrum of the ultrasonic probe at 15MHz is as follows Figure 4 shown.

[0074] (2) Calibrate on the residual stress test block. The residual str...

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Abstract

The invention provides a method for nondestructive evaluation of a residual stress of an aluminum alloy pre-stretched plate by utilizing an ultrasonic wave. The method comprises the following steps: selecting an ultrasonic wave characteristic frequency, and then obtaining a characteristic attenuation coefficient under the characteristic frequency; obtaining a surface roughness compensation coefficient, determining a grain size compensation coefficient of a detected aluminum alloy pre-stretched plate, determining a loosening compensation coefficient value of the aluminum alloy pre-stretched plate, determining a constant, related to a material characteristic, of the detected aluminum alloy pre-stretched plate, and then obtaining a residual stress value equation; selecting an ultrasonic wave probe; performing calibration on a residual stress test block, and performing correction on a system gain compensation; performing ultrasonic wave scanning on the to-be-detected plate; and generating a residual stress field map. Through adoption of the technical scheme, an influence of surface roughness is reduced, an obtained quantitative value of the residual stress is more accurate, the method has a large thickness application scope, and interferences of plate loosening and plate grain size factors on residual stress detection precision are reduced.

Description

technical field [0001] The invention belongs to the field of non-destructive testing, in particular to a method for ultrasonic non-destructive evaluation of the residual stress of an aluminum alloy pre-stretched plate. Background technique [0002] The modern aviation manufacturing industry is developing towards the direction of manufacturing large-scale integrated parts of aircraft. The existence of a large amount of residual stress in the aluminum alloy sheet will lead to serious consequences. The solution quenching process of 2XXX series and 7XXX series aluminum alloys is the main reason for introducing residual stress. However, in order to obtain better comprehensive properties after aging treatment, the solution quenching process of 2XXX series and 7XXX series aluminum alloys is essential. Manufacturers of aluminum alloy pre-stretched sheets often use large-tonnage pre-stretch machines to stretch the aluminum alloy sheets after solution quenching, so as to redistribut...

Claims

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Application Information

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IPC IPC(8): G01L1/25G01N29/04
Inventor 郑许郑玉林周文标赵解扬彭斐张良军何克准
Owner 广西南南铝加工有限公司
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